Effect of maduramicin on crayfish (Procambius clarkii): Hematological parameters, oxidative stress, histopathological changes and stress response.

Maduramicin, an extensively used anticoccidial drug, has been introduced into environment due to poorly absorbed in the intestine of broiler chicken. To understand the potential ecological toxicity of maduramicin on aquatic organisms, acute and subacute toxicity, hemolymph biochemistry, histopathology and the expressions of drug metabolism and stress response genes of crayfish (Procambius clarkii) were investigated in this study. For the first time, the 96 h median lethal concentration (LC) of maduramicin on crayfish was 67.03 mgL with a 95% confidence interval (54.06-81.32 mgL). Then, the crayfish were exposed to 0.7 mgL (1/100 LC), 3.5 mgL (1/20 LC) and 7.0 mgL (1/10 LC) maduramicin for 28 days. Maduramicin significantly altered biochemical parameters including AST, ALT, CK, LDH and ALP of hemolymph in crayfish at several time points. The activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) of crayfish gills, hepatopancreas and abdominal muscle were significantly decreased or elevated by different concentrations of maduramicin treatment at varying time points. Furthermore, histopathological damage of crayfish gills, hepatopancreas and abdominal muscle were observed in a concentration-dependent manner. The expressions of metabolic and stress response genes (CYP450, GST, COX1, COX2, HSP70 and MT) in hepatopancreas of crayfish were significantly up-regulated by maduramicin (7.0 mgL) treatment for 8 h to 7 d, and returned to normal levels after the removal of maduramicin for 3-7 days. In conclusion, our findings demonstrated that environmental exposure of maduramicin threaten to the health of crayfish living in the areas nearby livestock farms or pharmaceutical factory. Crayfish exhibited resistance to the stress of maduramicin via activating drug metabolite and detoxification pathways.